InterPro domain: IPR004161

Translation elongation factors are responsible for two main processes during protein synthesis on the ribosome [ 1 , 2 , 3 ]. EF1A (or EF-Tu) is responsible for the selection and binding of the cognate aminoacyl-tRNA to the A-site (acceptor site) of the ribosome. EF2 (or EF-G) is responsible for the translocation of the peptidyl-tRNA from the A-site to the P-site (peptidyl-tRNA site) of the ribosome, thereby freeing the A-site for the next aminoacyl-tRNA to bind. Elongation factors are responsible for achieving accuracy of translation and both EF1A and EF2 are remarkably conserved throughout evolution.

EF1A (also known as EF-1alpha or EF-Tu) is a G-protein. It forms a ternary complex of EF1A-GTP-aminoacyltRNA. The binding of aminoacyl-tRNA stimulates GTP hydrolysis by EF1A, causing a conformational change in EF1A that causes EF1A-GDP to detach from the ribosome, leaving the aminoacyl-tRNA attached at the A-site. Only the cognate aminoacyl-tRNA can induce the required conformational change in EF1A through its tight anticodon-codon binding [ 4 , 5 ]. EF1A-GDP is returned to its active state, EF1A-GTP, through the action of another elongation factor, EF1B (also known as EF-Ts or EF-1beta/gamma/delta).

EF1A consists of three structural domains. This entry represents domain 2 of EF2, which adopts a beta-barrel structure, and is involved in binding to both charged tRNA [ 6 ]. This domain is structurally related to the C-terminal domain of EF2 ( IPR004160 ), to which it displays weak sequence matches. This domain is also found in other proteins such as translation initiation factor IF-2 and tetracycline-resistance proteins.

1. Structural studies of eukaryotic elongation factors. Cold Spring Harb. Symp. Quant. Biol. 66, 425-37
2. Elongation factors on the ribosome. Curr. Opin. Struct. Biol. 15, 349-54
3. Elongation factors in protein biosynthesis. Trends Biochem. Sci. 28, 434-41
4. Recognition and selection of tRNA in translation. FEBS Lett. 579, 938-42
5. Mechanisms of EF-Tu, a pioneer GTPase. Prog. Nucleic Acid Res. Mol. Biol. 71, 513-51
6. Crystal structure of the ternary complex of Phe-tRNAPhe, EF-Tu, and a GTP analog. Science 270, 1464-72